WO2010140212A1

WO2010140212A1 - Control device for voltage conversion device, vehicle in which the same is installed, and control method for voltage conversion device

Info

Publication number: WO2010140212A1
Application number: PCT/JP2009/060029
Authority: WO
Inventors: 高松　直義; 賢樹岡村; 靖弘小池
Original assignee: トヨタ自動車株式会社; 株式会社豊田自動織機
Priority date: 2009-06-02
Filing date: 2009-06-02
Publication date: 2010-12-09
Also published as: JPWO2010140212A1; EP2439837A1; US20120081045A1; EP2439837A4; US8653772B2; JP5303030B2

Abstract

In a voltage conversion device (12) for a motor drive control device, switching for an upper arm (Q1) and a lower arm (Q2) that perform electrical power conversion by means of a switching operation is controlled so that the range of output voltage that can be output by the voltage conversion device (12), which is restricted by the dead time of the switching operation, is expanded. Thus, restriction of the output voltage of the voltage conversion device (12) that is caused by the dead time can be suppressed.

Description

Control device for voltage converter, vehicle equipped with the same, and control method for voltage converter

The present invention relates to a control device for a voltage conversion device, a vehicle on which the voltage conversion device is mounted, and a control method for the voltage conversion device, and more particularly to suppression of output voltage limitation of the voltage conversion device caused by dead time.

2. Description of the Related Art In recent years, as an environmentally friendly vehicle, an electric vehicle that is mounted with a power storage device (for example, a secondary battery or a capacitor) and travels using a driving force generated from the electric power stored in the power storage device has attracted attention. Examples of the electric vehicle include an electric vehicle, a hybrid vehicle, and a fuel cell vehicle.

In these electric vehicles, a motor generator for generating driving force for traveling by receiving electric power from the power storage device when starting or accelerating, and generating electric power by regenerative braking during braking to store electric energy in the power storage device May be provided. Thus, in order to control a motor generator according to a driving | running | working state, an inverter is mounted in an electric vehicle.

In such a vehicle, a voltage converter (converter) may be provided between the power storage device and the inverter in order to stably supply electric power required by the inverter that varies depending on the vehicle state. This converter also makes it possible to increase the input voltage of the inverter higher than the output voltage of the power storage device to increase the output of the motor and reduce the motor current at the same output, thereby reducing the size and the size of the inverter and the motor. Cost can be reduced.

Japanese Patent Laid-Open No. 2006-187186 (Patent Document 1) describes a voltage conversion device for a motor drive device in which the switching element of the voltage conversion device has a dead time in a region where the voltage command value of the voltage conversion device is close to the power supply voltage. A technique for reducing the carrier frequency used for switching control of the switching element when affected is disclosed.

According to this technique, in the region where the voltage command value of the voltage converter is close to the power supply voltage, that is, in the region where the on-duty of the upper arm of the voltage converter is very close to 1.0, the on-duty originally targeted by the dead time The oscillation of the output voltage occurs due to the inability to ensure. According to this technique, the oscillation of the output voltage of the voltage converter can be suppressed.

JP 2006-187186 A JP 2008-302763 A JP 2004-112904 A

In power converters such as inverters and converters, in order to reduce the size of the device itself and the noise generated by switching, the carrier frequency in switching control is being increased.

When the carrier frequency for switching control is increased, the switching cycle of the switching element is shortened. Then, if the operating speed of the switching elements is the same, the dead time in switching per time does not change, and therefore the ratio of dead time in the switching period increases compared to the case where the frequency is not increased. As a result, the desired on-duty may not be ensured even if the on-duty is not very close to 1.0, so that the voltage range that can be output by the voltage converter is limited. There is.

The present invention has been made to solve such a problem, and an object of the present invention is to suppress the output voltage limitation of the voltage converter caused by dead time in the voltage converter in the motor drive control device. It is to be.

A control device for a voltage conversion device according to the present invention is a control device for a voltage conversion device capable of voltage conversion between a power storage device and a load device. The voltage conversion device includes a first switching element and a second switching element that are connected in series between the power line and the ground line of the load device and perform voltage conversion by a switching operation. Further, the switching operation includes a dead time that is a period during which both the first switching element and the second switching element are in the OFF state. The control device is configured to control the switching of the first switching element and the second switching element based on the frequency setting unit that sets the carrier frequency of the switching operation, and the voltage command value and the carrier frequency of the voltage conversion. A drive control unit. Then, the drive control unit, based on the information related to the power input / output to / from the voltage conversion device, expands the output voltage range of the voltage conversion device limited by the dead time, and the first switching element and the first switching device. Switching control of the switching element 2 is performed.

Preferably, the information related to the power input / output to / from the voltage converter is the target duty of the first switching element and the second switching element. The drive control unit calculates a target value calculation unit configured to calculate a target duty based on the voltage command value, and a duty range that determines an output possible voltage range based on the carrier frequency and dead time. And a reference value calculation unit configured as described above. Then, when the target duty exceeds the duty range, the drive control unit performs switching control so as to expand the output possible voltage range.

Also preferably, the drive control unit further includes a frequency changing unit configured to lower the carrier frequency when the target duty exceeds the duty range.

Alternatively, preferably, when the target duty exceeds the duty range, the drive control unit selects one of the first switching element and the second switching element, while when the target duty is within the duty range. It further includes a selection unit configured to select both the first switching element and the second switching element, and a drive command generation unit that generates a drive command for the switching element selected by the selection unit.

Also preferably, the selection unit selects the second switching element when the target duty is larger than the upper limit value of the duty range.

Alternatively, preferably, the selection unit selects the first switching element when the target duty is smaller than a lower limit value of the duty range.

Preferably, the frequency setting unit variably sets the carrier frequency based on information related to power input / output to / from the voltage converter.

Also preferably, the information related to the power input / output to / from the voltage conversion device includes at least one of output power, output voltage, and output current of the power storage device.

Alternatively, or preferably, the voltage conversion device further includes a reactor provided in a path connecting the connection node of the first switching element and the second switching element and the positive electrode terminal of the power storage device. And the information relevant to the electric power input / output to / from the voltage converter includes the reactor current flowing through the reactor.

Alternatively, or preferably, the information related to the power input / output to / from the voltage converter includes power supplied to the load device.

[Correction based on Rule 91 17.06.2010]
A vehicle according to the present invention includes a power storage device, a rotating electrical machine, an inverter, a voltage conversion device, and a control device. The rotating electrical machine generates a driving force for propelling the vehicle. The inverter drives the rotating electrical machine. The voltage conversion device is configured to be capable of voltage conversion between the power storage device and the inverter. The control device controls the voltage conversion device. The voltage conversion device includes a first switching element and a second switching element that are connected in series between the power line and the ground line of the load device and perform voltage conversion by a switching operation. The switching operation includes a dead time during which both the first switching element and the second switching element are in the off state. Further, the control device is configured to control the switching of the first switching element and the second switching element based on the frequency setting unit that sets the carrier frequency of the switching operation and the voltage command value and the carrier frequency of the voltage conversion. Drive control unit. Then, the drive control unit, based on the information related to the power input / output to / from the voltage converter, expands the output possible voltage range of the voltage converter limited by the dead time, and the first switching element and the first Switching control of the switching element 2 is performed.

Preferably, the information related to the power input / output to / from the voltage converter is the target duty of the first switching element and the second switching element. The drive control unit calculates a target value calculation unit configured to calculate a target duty based on the voltage command value, and a duty range that determines an output possible voltage range based on the carrier frequency and dead time. And a reference value calculation unit configured as described above. When the target duty exceeds the duty range, the drive control unit performs switching control so as to expand the output possible voltage range.

Alternatively, preferably, when the target duty exceeds the duty range, the drive control unit selects one of the first switching element and the second switching element while the target duty is within the duty range. Further includes a selection unit configured to select both the first switching element and the second switching element, and a drive command generation unit configured to generate a drive command for the switching element selected by the selection unit.

The voltage conversion device control method according to the present invention is a voltage conversion device control method capable of voltage conversion between a power storage device and a load device. The voltage conversion device includes a first switching element and a second switching element that are connected in series between the power line and the ground line of the load device and perform voltage conversion by a switching operation. In addition, the switching operation includes a dead time that is a period during which both the first switching element and the second switching element are in the OFF state. And the control method of a voltage converter is the step which sets the carrier frequency of switching operation, and the step which carries out switching control of the 1st switching element and the 2nd switching element based on the voltage command value and carrier frequency of voltage conversion And the first switching element and the second switching element so as to expand the output possible voltage range of the voltage conversion device limited by the dead time based on information related to the power input / output to / from the voltage conversion device. Performing switching control.

According to the present invention, in the voltage conversion device in the motor drive control device, it is possible to suppress the output voltage limitation of the voltage conversion device caused by dead time.

1 is an overall configuration diagram of a hybrid vehicle equipped with a motor drive control system to which an AC motor control device according to Embodiment 1 is applied. It is a time chart for demonstrating the influence of the dead time in switching control. It is a time chart for demonstrating an actual duty when a load apparatus is a power running state, and a reactor current becomes always positive. It is a figure for demonstrating the electric current which flows through a converter in the case of FIG. It is a time chart for demonstrating an actual duty in the case of the time of the low load when the reactor current in a power running state is near zero. It is a figure for demonstrating the electric current which flows through the converter in the case of FIG. It is a time chart for demonstrating an actual duty when a load apparatus is a regenerative state and a reactor current is always negative. It is a figure for demonstrating the electric current which flows through the converter in the case of FIG. It is a figure which shows the relationship between the output current of an electrical storage apparatus, output electric power, and an output voltage in a power running state. It is the time chart which compared the duty in a power running state in the case where there is no influence of dead time and it is. 3 is a time chart for explaining an actual duty when the converter drive control of the first embodiment is applied in the power running state of FIG. FIG. 3 is a functional block diagram for illustrating converter drive control executed by an ECU in the first embodiment. 4 is a flowchart for illustrating details of converter drive control processing executed by the ECU in the first embodiment. 3 is a time chart for explaining an actual duty when the converter drive control of the second embodiment is applied in the power running state of FIG. FIG. 6 is a functional block diagram for illustrating converter drive control executed by an ECU in the second embodiment. 6 is a flowchart for illustrating details of converter drive control processing executed by an ECU in the second embodiment. FIG. 10 is a functional block diagram for illustrating converter drive control executed by an ECU in the third embodiment. It is a figure which shows the 1st example of the map for setting a carrier frequency. It is a figure which shows the 2nd example of the map for setting a carrier frequency. It is a figure which shows the 3rd example of the map for setting a carrier frequency. 12 is a flowchart for illustrating details of converter drive control processing executed by an ECU in the third embodiment. It is a functional block diagram for demonstrating converter drive control performed by ECU at the time of combining Embodiment 1 and Embodiment 3. FIG. It is a flowchart for demonstrating the detail of the converter drive control process performed by ECU at the time of combining Embodiment 1 and Embodiment 3. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the same or equivalent part in a figure, the same code | symbol is attached | subjected and the description is not repeated.

[Embodiment 1]
FIG. 1 is an overall configuration diagram of a hybrid vehicle 100 equipped with a motor drive control system to which an AC motor control device according to Embodiment 1 is applied. In the first embodiment, a hybrid vehicle equipped with an engine and a motor generator will be described as an example of vehicle 100. However, the configuration of vehicle 100 is not limited to this, and the vehicle can travel with electric power from a power storage device. If so, it is applicable. The vehicle 100 includes, for example, an electric vehicle and a fuel cell vehicle in addition to the hybrid vehicle.

In the present embodiment, a configuration in which the motor drive control system is applied to the vehicle will be described. However, the present motor drive control system can be applied to any device that is driven by an AC motor other than the vehicle.

Referring to FIG. 1, vehicle 100 includes a DC voltage generation unit 20, a load device 45, a smoothing capacitor C 2, and a control device (hereinafter also referred to as ECU “Electronic Control Unit”) 30.

DC voltage generation unit 20 includes a power storage device 28, system relays SR1 and SR2, a smoothing capacitor C1, and a converter 12.

The power storage device 28 is typically configured to include a power storage device such as a secondary battery such as nickel hydride or lithium ion or an electric double layer capacitor. Further, DC voltage VB output from power storage device 28 and DC current IB input / output are detected by voltage sensor 10 and current sensor 11, respectively. Voltage sensor 10 and current sensor 11 output detected values of detected DC voltage VB and DC current IB to ECU 30.

System relay SR1 is connected between the positive terminal of power storage device 28 and power line PL1, and system relay SR2 is connected between the negative terminal of power storage device 28 and ground line NL. System relays SR 1 and SR 2 are controlled by a signal SE from ECU 30, and switch between supply and interruption of power from power storage device 28 to converter 12.

Converter 12 includes a reactor L1, an upper arm including switching element Q1 and diode D1, and a lower arm including switching element Q2 and diode D2. Switching elements Q1 and Q2 are connected in series between power line PL2 and ground line NL. Switching elements Q1 and Q2 are controlled by a switching control signal PWC from ECU 30.

In the present embodiment, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, a power bipolar transistor, or the like can be used as the switching element. Anti-parallel diodes D1 and D2 are arranged for switching elements Q1 and Q2. Reactor L1 is connected between connection node V0 of switching elements Q1 and Q2 and power line PL1. Smoothing capacitor C2 is connected between power line PL2 and ground line NL.

The current sensor 18 detects the reactor current flowing through the reactor L1, and outputs the detected value IL to the ECU 30. In the present embodiment, reactor current IL is positive in the direction from power storage device 28 to load device 45 and negative in the direction from load device 45 to power storage device 28.

The load device 45 includes an inverter 23, motor generators MG1 and MG2, an engine 40, a power split mechanism 41, and drive wheels 42. Inverter 23 includes an inverter 14 for driving motor generator MG1 and an inverter 22 for driving motor generator MG2. As shown in FIG. 1, it is not essential to provide two sets of inverters and motor generators. For example, only one set of inverter 14 and motor generator MG1 or inverter 22 and motor generator MG2 may be provided.

Motor generators MG1 and MG2 receive AC power supplied from inverter 23 and generate a rotational driving force for vehicle propulsion. Motor generators MG1 and MG2 receive rotational force from the outside, generate AC power according to a regenerative torque command from ECU 30, and generate regenerative braking force in vehicle 100.

Motor generators MG1 and MG2 are also coupled to engine 40 via power split mechanism 41. Then, the driving force generated by engine 40 and the driving force generated by motor generators MG1, MG2 are controlled to have an optimal ratio. Alternatively, either one of motor generators MG1 and MG2 may function exclusively as an electric motor, and the other motor generator may function exclusively as a generator. In the first embodiment, it is assumed that motor generator MG1 functions as a generator driven by engine 40, and motor generator MG2 functions as an electric motor that drives drive wheels 42.

The power split mechanism 41 uses a planetary gear mechanism (planetary gear) in order to distribute the power of the engine 40 to both the drive wheels 42 and the motor generator MG1.

Inverter 14 receives the boosted voltage from converter 12, and drives motor generator MG1 to start engine 40, for example. Inverter 14 also outputs regenerative power generated by motor generator MG 1 by mechanical power transmitted from engine 40 to converter 12. At this time, converter 12 is controlled by ECU 30 to operate as a step-down circuit.

The inverter 14 is provided in parallel between the power line PL2 and the ground line NL, and includes a U-phase upper and lower arm 15, a V-phase upper and lower arm 16, and a W-phase upper and lower arm 17. Each phase upper and lower arm is formed of a switching element connected in series between power line PL2 and ground line NL. For example, the U-phase upper / lower arm 15 includes switching elements Q3, Q4, the V-phase upper / lower arm 16 includes switching elements Q5, Q6, and the W-phase upper / lower arm 17 includes switching elements Q7, Q8. Composed. Antiparallel diodes D3 to D8 are connected to switching elements Q3 to Q8, respectively. Switching elements Q3-Q8 are controlled by switching control signal PWI from ECU 30.

Typically, motor generator MG1 is a three-phase permanent magnet synchronous motor, and one end of three U, V, and W phase coils is commonly connected to a neutral point. Further, the other end of each phase coil is connected to a connection node of switching elements of each phase upper and lower arms 15 to 17.

Inverter 22 is connected to converter 12 in parallel with inverter 14.
Inverter 22 converts the DC voltage output from converter 12 into three-phase AC and outputs the same to motor generator MG2 that drives drive wheels. Inverter 22 also outputs regenerative power generated by motor generator MG2 to converter 12 along with regenerative braking. At this time, converter 12 is controlled by ECU 30 to operate as a step-down circuit. Although the internal configuration of inverter 22 is not shown, it is similar to inverter 14, and detailed description will not be repeated.

The converter 12 is basically controlled so that the switching elements Q1 and Q2 are turned on and off in a complementary manner within each switching period. Converter 12 boosts DC voltage VB supplied from power storage device 28 to DC voltage VH (hereinafter, this DC voltage corresponding to the input voltage to inverter 14 is also referred to as “system voltage”) during the boosting operation. This boosting operation is performed by supplying the electromagnetic energy accumulated in reactor L1 during the ON period of switching element Q2 to power line PL2 via switching element Q1 and antiparallel diode D1.

Further, converter 12 steps down DC voltage VH to DC voltage VB during the step-down operation. This step-down operation is performed by supplying the electromagnetic energy stored in reactor L1 during the ON period of switching element Q1 to ground line NL via switching element Q2 and antiparallel diode D2.

The voltage conversion ratio (ratio of VH and VB) in these step-up and step-down operations is controlled by the on-period ratio (duty ratio) of the switching elements Q1 and Q2 in the switching period. If switching elements Q1 and Q2 are fixed on and off, respectively, VH = VB (voltage conversion ratio = 1.0) can be obtained.

Smoothing capacitor C 2 smoothes the DC voltage from converter 12 and supplies the smoothed DC voltage to inverter 23. The voltage sensor 13 detects the voltage across the smoothing capacitor C2, that is, the system voltage VH, and outputs the detected value to the ECU 30.

When the torque command value of motor generator MG1 is positive (TR1> 0), inverter 14 has switching elements Q3 to Q8 responding to switching control signal PWI1 from ECU 30 when a DC voltage is supplied from smoothing capacitor C2. By the switching operation, motor generator MG1 is driven so as to convert a DC voltage into an AC voltage and output a positive torque. Further, when the torque command value of motor generator MG1 is zero (TR1 = 0), inverter 14 converts the DC voltage into the AC voltage and the torque becomes zero by the switching operation in response to switching control signal PWI1. In this manner, motor generator MG1 is driven. Thus, motor generator MG1 is driven to generate zero or positive torque designated by torque command value TR1.

Furthermore, during regenerative braking of vehicle 100, torque command value TR1 of motor generator MG1 is set negative (TR1 <0). In this case, inverter 14 converts the AC voltage generated by motor generator MG1 into a DC voltage by a switching operation in response to switching control signal PWI1, and converts the converted DC voltage (system voltage) through smoothing capacitor C2. To the converter 12. The regenerative braking here refers to braking with regenerative power generation when the driver operating the electric vehicle performs a footbrake operation, or regenerative braking by turning off the accelerator pedal while driving, although the footbrake is not operated. This includes decelerating (or stopping acceleration) the vehicle while generating electricity.

Similarly, inverter 22 receives switching control signal PWI2 from ECU 30 corresponding to the torque command value of motor generator MG2 and converts the DC voltage into an AC voltage by a switching operation in response to switching control signal PWI2 to obtain a predetermined torque. Motor generator MG2 is driven so that

Current sensors

24 and 25 detect motor currents MCRT1 and MCRT2 flowing through motor generators MG1 and MG2, and output the detected motor currents to ECU 30. Since the sum of the instantaneous values of the currents of the U-phase, V-phase, and W-phase is zero, the

current sensors

24 and 25 are arranged to detect the motor current for two phases as shown in FIG. All you need is enough.

Rotation angle sensors (resolvers) 26 and 27 detect rotation angles θ1 and θ2 of motor generators MG1 and MG2, and send the detected rotation angles θ1 and θ2 to ECU 30. ECU 30 can calculate rotational speeds MRN1, MRN2 and angular speeds ω1, ω2 (rad / s) of motor generators MG1, MG2 based on rotational angles θ1, θ2. The

rotation angle sensors

26 and 27 may not be arranged by directly calculating the rotation angles θ1 and θ2 from the motor voltage and current in the ECU 30.

The ECU 30 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer (not shown), and controls each device of the vehicle 100. Note that these controls are not limited to software processing, and can be constructed and processed by dedicated hardware (electronic circuit).

As representative functions, the ECU 30 includes the input torque command values TR1 and TR2, the DC voltage VB detected by the voltage sensor 10, the DC current IB detected by the current sensor 11, and the system voltage detected by the voltage sensor 13. Based on VH, motor currents MCRT1, MCRT2 from

current sensors

24, 25, rotation angles θ1, θ2 from

rotation angle sensors

26, 27, etc., motor generators MG1, MG2 generate torques according to torque command values TR1, TR2. The operations of the converter 12 and the inverter 23 are controlled so as to output. That is, switching control signals PWC, PWI1, and PWI2 for controlling converter 12 and inverter 23 as described above are generated and output to converter 12 and inverter 23, respectively.

During the step-up operation of converter 12, ECU 30 feedback-controls system voltage VH and generates switching control signal PWC so that system voltage VH matches the voltage command value.

Further, when the vehicle 100 enters the regenerative braking mode, the ECU 30 generates the switching control signals PWI1 and PWI2 so as to convert the AC voltage generated by the motor generators MG1 and MG2 into a DC voltage, and outputs the switching control signals PWI1 and PWI2. Thus, inverter 23 converts the AC voltage generated by motor generators MG1 and MG2 into a DC voltage and supplies it to converter 12.

Furthermore, when the vehicle 100 enters the regenerative braking mode, the ECU 30 generates a switching control signal PWC so as to step down the DC voltage supplied from the inverter 23 and outputs it to the converter 12. Thus, the AC voltage generated by motor generators MG1 and MG2 is converted into a DC voltage, and is further stepped down and supplied to power storage device 28.

A state where the reactor average current obtained by averaging the reactor current flowing through reactor L1 in the time axis direction is positive is a power running state in which motor generators MG1 and MG2 are driven by electric power from power storage device 28, and a state where reactor average current is negative The electric power generated by motor generators MG1 and MG2 is in a regenerative state in which power storage device 28 is charged. Depending on the traveling state of vehicle 100, motor generators MG1 and MG2 may have different states (powering and regeneration). For example, the motor generator MG1 is driven in the regenerative state while the motor generator MG2 is driven in the power running state. Therefore, in the following description, the case where power is supplied from the power storage device 28 to the load device 45 is collectively referred to as a power running state, and the power generated by the load device 45 is charged to the power storage device 28. Are collectively called the regenerative state.

FIG. 2 is a time chart for explaining the influence of dead time in switching control. In FIG. 2, the horizontal axis represents time, and the vertical axis represents the carrier wave (carrier wave) in the switching control, the operating state of the switching elements Q1 and Q2, and the voltage of the connection node V0. FIG. 2 shows an example in the case where the load device 45 is in a power running state and the reactor current IL is always positive at a high load.

Referring to FIG. 2, the drive command for switching elements Q1, Q2 is basically generated by comparing the carrier wave with the command duty. For example, in FIG. 2, when the command duty is W2, in the switching cycle T from time t1 to t4, between the intersection A1 and the intersection A2 between the carrier wave W1 and the command duty W2 (that is, from time t1 to t2). ), Switching element Q1 is controlled to be on (switching element Q2 is off), and switching element Q1 is controlled to be off (switching element Q2 is on) between intersection A2 and intersection A3 (ie, from time t2 to t4). Is done.

Therefore, when the command duty becomes 1.0, the switching element Q1, which is the upper arm, is always controlled to be on, and the switching element Q2 is always controlled to be off. On the contrary, when the command duty becomes 0.0, the switching element Q1, which is the upper arm, is always controlled to be off, and the switching element Q2 is always controlled to be on.

However, in actual control, in consideration of the operation speed of the switching elements, the switching elements Q1 and Q2 are simultaneously turned on to prevent the power line PL2 and the ground line NL from being short-circuited. After the switching element is turned off, a period (dead time) in which the other switching element is not turned on is provided for a certain time.

Also, since the switching element itself requires an operation time when operating from off to on or from on to off, a minimum on time (or minimum off time) of the switching element is required. Therefore, the actual duty (hereinafter also referred to as “actual duty”) may be limited by the dead time and the minimum on-time (or minimum off-time) of the switching element.

In FIG. 2, the OFF period of the switching element Q2 should be between the intersection A1 and the intersection A2 (time t1 to t2). However, depending on the dead time and the minimum ON time of the switching element Q1, From time t1 to t3, the switching element Q2 is turned off.

At this time, during the dead time, the direction of the current flowing through the circuit varies depending on the operating state of the load, as will be described in detail later with reference to FIGS.

In FIG. 2, since the reactor current IL is always positive as described above, the current flows to the upper arm side even during the dead time period.

Therefore, the voltage of the connection node V0 becomes the system voltage VH from time t1 to time t3 (time T1). Therefore, the actual duty limited by the dead time and the minimum on-time of the switching element is expressed by the ratio that the voltage of the connection node V0 of the switching elements Q1 and Q2 becomes the system voltage during the switching period T, that is, T1 / T. Can do.

Next, the difference in the actual duty when the load operating state is different will be described with reference to FIGS.

FIG. 3 is a time chart for explaining the actual duty when the load device 45 is in the power running state and the reactor current IL is always positive, as in FIG. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the reactor current IL, the carrier wave, the operating state of the switching elements Q1, Q2, and the voltage of the connection node V0.

The drive command for the switching elements Q1 and Q2 is generated by comparing the carrier wave with the command duty. However, as described above, the actual operation is restricted by the dead time and the minimum on-time of the switching element.

FIG. 4 is a diagram for explaining the current flowing through the converter 12 in the case of FIG. Referring to FIGS. 3 and 4, in the case of FIG. 3, when switching element Q2 is on, current flows from power line PL1 through reactor L1 and switching element Q2, as indicated by solid line arrow AR1 in FIG. And flows in a direction toward the ground line NL. At this time, positive energy is accumulated in reactor L1. When the switching element Q2 is turned off, the switching element Q1 is then turned on. However, in the case of FIG. 3, during the period in which switching element Q2 is off (ie, the dead time period and the period in which switching element Q1 is on), the current passes through diode D1 due to the positive energy accumulated in reactor L1. And flows in the direction from the reactor L1 toward the power line PL2 (solid arrow AR2 in FIG. 4).

Thus, the voltage of the connection node V0 is always the system voltage VH while the switching element Q2 is off. Therefore, the actual duty is a ratio of time in the switching period T, which is the sum of the dead time and the ON time of the switching element Q1.

FIG. 5 is a time chart for explaining the actual duty when the reactor current is in a power running state but the reactor current is at a low load close to zero. FIG. 5 shows the same command duty as FIG. 3, but the reactor current IL is switched from positive to negative or from negative to positive during the switching period.

FIG. 6 is a diagram for explaining the current flowing through the converter 12 in the case of FIG. 5 and FIG. 6, immediately after switching element Q2 is switched from on to off, reactor current IL is positive, so that the current passes through diode D1 as in FIG. It flows in the direction of solid line arrow AR2 in FIG. Thereafter, switching element Q1 is turned on. However, when the current decreases to zero, current flows in the direction from power line PL2 to power line PL1 via switching element Q1 (broken arrow AR4 in FIG. 6). start. As a result, negative energy is accumulated in reactor L1.

A dead time period until switching element Q1 is turned off and switching element Q2 is turned on, and after switching element Q2 is turned on, until the release of negative energy accumulated in reactor L1 is completed, ground line NL Through the diode D2, the current flows in the direction toward the reactor L1 (broken line arrow AR3 in FIG. 6).

Thereafter, when the release of the energy accumulated in reactor L1 is completed, this time, the direction toward the ground line NL from power line PL1 via reactor L1 and switching element Q2 by the output power from power storage device 28 (in FIG. 6). Current flows through the solid arrow AR1). As a result, positive energy is accumulated in reactor L1.

Thus, when the reactor current IL is switched from positive to negative, or from negative to positive, the voltage at the connection node V0 is zero during the dead time period when the reactor current IL is negative. Therefore, the actual duty is a ratio of time during which the switching element Q1 is turned on and the dead time from switching element Q2 off to switching element Q1 on is added in the switching period T.

FIG. 7 is a time chart for explaining the actual duty when the load device 45 is in the regenerative state and the reactor current IL is always negative. FIG. 8 is a diagram for explaining the current flowing through converter 12 in the case of FIG. Further, the command duty in FIG. 7 is the same as in FIGS. 3 and 5.

Referring to FIGS. 7 and 8, since reactor current IL is negative when switching element Q1 is on, the current flows from power line PL2 to reactor L1 via switching element Q1 (in FIG. 8). It flows in the broken line arrow AR4).

Then, although the switching element Q1 is turned off, a dead time period until the switching element Q2 is subsequently turned on, a period during which the switching element Q2 is turned on, and a period from when the switching element Q2 is turned off until the switching element Q1 is turned on Since the reactor current IL is in a negative state in any period of the dead time period, a current flows in the direction from the ground line NL to the reactor L1 via the diode D2 (broken line arrow AR3 in FIG. 8).

Thus, in the case of FIG. 7, the period during which the voltage at the connection node V0 is the system voltage VH is only the period during which the switching element Q1 is on. Therefore, the actual duty is a ratio of the on-time of the switching element Q1 in the switching period T.

Thus, since the direction of the current flowing during the dead time period varies depending on the load state, when the on-duty is eroded by the dead time in a state where the command duty is close to 0 or 1, The command duty cannot be achieved.

FIG. 9 is a diagram showing the relationship between the output current IB of the power storage device 28, the output power POUT, and the output voltage VB in the power running state. In FIG. 9, the horizontal axis indicates the output current IB, and the vertical axis indicates the output voltage VB (upper stage) and the output power POUT (lower stage). In the following description, the case of the power running state will be described as an example, but the same applies to the case of the regenerative state.

Referring to FIG. 9, output voltage VB of power storage device 28 can be expressed as equation (1), where VB0 is the open circuit voltage of power storage device 28 and RB is the internal resistance.

VB = VB0−IB · RB (1)
This is illustrated as a straight line W10 in the upper part of FIG.

[Correction based on Rule 91 17.06.2010]
Output power POUT of power storage device 28 can be represented by the product of output voltage VB and output current IB.

POUT = VB · IB (2)
Substituting equation (1) into equation (2) yields equation (3).

POUT = (VB0−IB · RB) · IB (3)
By transforming this, equation (4) is obtained.

POUT = −RB · {IB− (VB0 / 2RB)} ² + (VB0 ² / 4RB ² ) (4)
When this is illustrated, a parabola such as a curve W20 in FIG. 9 is obtained.

Note that when the output current IB is larger than IB0, the power consumed by the internal resistance of the power storage device 28 is large (output excessive range), and therefore, normally the output current is used in the range of 0 to IB0 (normal range). The

9 and formula (4), the maximum power Pmax that can be taken out from the power storage device 28 is the case where the output current IB in FIG. 9 is IB0 (= VB0 / 2RB). The output voltage is VB0 / 2.

That is, if the duty (VB / VH) for driving the converter 12 is set to VB0 / 2VH, the maximum power can be taken out from the power storage device 28.

However, as described with reference to FIGS. 3 to 8, when there is an influence of the dead time of the switching elements Q1 and Q2, the on-duty may be eroded by the dead time, and the command duty may not be achieved. . In this case, the electric power from the power storage device 28 cannot be drawn sufficiently, so that the desired system voltage VH cannot be achieved, and the power performance may be insufficient.

FIG. 10 is a time chart comparing the duty in the power running state with and without the influence of the dead time. The upper part of FIG. 10 shows the carrier wave, and the middle part shows the operating state of the switching elements Q1 and Q2 and the voltage of the connection node V0 in an ideal case without the influence of the dead time. Further, the lower part of FIG. 10 shows the operation state of the switching elements Q1 and Q2 in the actual case in consideration of the dead time and the voltage of the connection node V0.

Referring to FIG. 10, since the duty when there is no influence of the dead time coincides with the command duty, it becomes a ratio (T1 / T) of the ON time of the switching element Q1 in the switching period T.

In the case where there is an influence of the dead time, as described with reference to FIG. 3, since the current flows through the diode D1 during the dead time period, the actual duty is T1A / T.

Here, since T1 <T1A, as shown in the upper part of FIG. 10, the actual duty becomes larger than the command duty, and the period (T2A) during which the switching element Q2 is on becomes shorter than T2.

When boosting with the converter 12, in order to increase the boosting ratio (VH / VB), it is necessary to increase the on-time of the switching element Q2 and increase the energy stored in the reactor L1, but the above-mentioned As described above, if the actual duty is limited by the dead time, the energy stored in the reactor L1 becomes small, so that a desired boost ratio cannot be achieved.

Particularly in winter and cold regions, when the temperature of the power storage device 28 decreases, the output voltage VB of the power storage device 28 decreases. As a result, the step-up ratio required for the target system voltage VH increases, and if the target duty cannot be achieved, the power required for driving the motor cannot be obtained and the power performance may be degraded. .

In recent years, in power converters such as converters and inverters, in order to reduce the size of the device itself and to suppress noise generated by switching, the carrier frequency in switching control has been increased. As a result, the proportion of the dead time during the switching period increases, and the number of cases where the desired boost ratio cannot be achieved increases.

Therefore, in the first embodiment, when the target output voltage of converter 12 exceeds the voltage range that can actually be set due to the influence of the dead time of switching elements Q1, Q2, that is, the command duty is the dead time of switching elements Q1, Q2. When the actual duty range that can be set is exceeded due to the influence of time, converter drive control is performed to set the carrier frequency lower than in the normal case.

By doing so, when the output voltage is limited at a low temperature or the like, the influence of the dead time can be reduced by lowering the carrier frequency, so that the target output voltage can be obtained. . Further, when the target output voltage is within the settable voltage range, the carrier frequency can be increased.

FIG. 11 is a time chart for explaining the actual duty when the converter drive control according to the first embodiment is applied in the power running state shown in FIG.

2 and 11, when the converter drive control in the first embodiment is applied, the target output voltage of converter 12 can be actually set within the voltage range due to the influence of the dead time of switching elements Q1 and Q2. Is exceeded, the carrier frequency is set low as shown in FIG. As a result, the switching period is changed from T to T # (T <T #).

Here, since the operating speed of the switching elements Q1 and Q2 does not change, the setting of the dead time per time does not need to be changed. Therefore, the ratio of the dead time in the switching cycle T # is smaller than that in the case where the first embodiment is not applied. As a result, the range that the actual duty (T1 # / T #) can be increased.

FIG. 12 is a functional block diagram for explaining converter drive control executed by the ECU 30 in the first embodiment. Each functional block described in the functional block diagram illustrated in FIG. 12 and the subsequent FIGS. 15, 17, and 22 is realized by hardware or software processing by the ECU 30.

Referring to FIGS. 1 and 12, ECU 30 includes a frequency setting unit 300, a voltage command setting unit 310, and a drive control unit 320. Further, the drive control unit 320 includes a target value calculation unit 330, a reference value calculation unit 340, a selection unit 350, a frequency change unit 360, an oscillation unit 370, and a drive command generation unit 380.

The frequency setting unit 300 sets a preset carrier frequency FC. In the first embodiment, this carrier frequency FC is a fixed value. Then, the frequency setting unit 300 outputs the set carrier frequency FC to the reference value calculation unit 340 and the frequency change unit 360.

Based on the carrier frequency FC from the frequency setting unit 300 and the preset dead time and minimum on-time of the switching elements Q1 and Q2, the reference value calculation unit 340 has a settable actual duty that takes into account the dead time. The upper limit value UL and the lower limit value LL of the range are calculated. Then, the reference value calculation unit 340 outputs the calculation result to the selection unit 350.

Voltage command setting unit 310 receives input of torque command values TR1, TR2 of motor generators MG1, MG2 and rotational speeds MRN1, MRN2 of motor generators MG1, MG2. Based on these pieces of information, voltage command setting unit 310 calculates voltage command value VHREF of input voltage (system voltage) VH of inverter 23, and outputs it to target value calculation unit 330.

The target value calculation unit 330 receives an input of the voltage command value VHREF from the voltage command setting unit 310. Target value calculation unit 330 receives input of output voltage VB and system voltage VH of power storage device 28 detected by voltage sensors 10 and 13, respectively.

The target value calculation unit 330 calculates a command duty DUTY based on these pieces of information. Then, the target value calculation unit 330 outputs the calculation result to the selection unit 350 and the drive command generation unit 380.

The selection unit 350 receives the upper limit value UL and the lower limit value LL of the settable duty range from the reference value calculation unit 340 and the command duty DUTY from the target value calculation unit 330. Then, selection unit 350 determines whether or not command duty DUTY is within a settable duty range. Then, the selection unit 350 sets the change flag FLG to OFF when the command duty DUTY is within the settable duty range, and sets the change flag FLG when the command duty DUTY exceeds the settable duty range. Set to on. Then, selection unit 350 outputs change flag FLG to frequency change unit 360.

The frequency change unit 360 receives the carrier frequency FC from the frequency setting unit 300 and the change flag FLG from the selection unit 350. Then, when the change flag FLG is off, the frequency changing unit 360 sets the carrier frequency FC received from the frequency setting unit 300 to the carrier frequency FC * for use in the oscillating unit 370. On the other hand, when the change flag is on, the frequency changing unit 360 sets the carrier frequency FC * for use in the oscillating unit 370 to a frequency lower than the carrier frequency FC. Then, the frequency changing unit 360 outputs the set carrier frequency FC * to the oscillating unit 370.

Note that the frequency change in the frequency changing unit 360 may be changed to a preset fixed frequency, or variably according to the difference between the command duty and the above-described upper limit value UL or lower limit value LL. It may be changed.

The oscillation unit 370 generates a carrier wave CAR according to the carrier frequency FC * received from the frequency changing unit 360, and outputs the carrier wave CAR to the drive command generating unit 380.

The drive command generator 380 receives the input of the carrier wave CAR from the oscillator 370 and the command duty DUTY from the target value calculator 330. Drive command generation unit 380 generates switching control command PWC for driving switching elements Q1 and Q2 based on the comparison between carrier wave CAR and command duty DUTY and outputs the switching control command PWC to converter 12.

FIG. 13 is a flowchart for illustrating details of the converter drive control process executed by ECU 30 in the first embodiment. Each step in the flowcharts of FIG. 13 and the subsequent FIG. 16, FIG. 21, FIG. 23 is realized by executing a program stored in the ECU 30 in a predetermined cycle. Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing.

Referring to FIGS. 12 and 13, ECU 30 sets carrier frequency FC to a predetermined initial value (FC0) in frequency setting unit 300 in step (hereinafter, step is abbreviated as S) 400.

Next, in S410, ECU 30 based on voltage command value VHREF of the output voltage of converter 12 calculated based on torque command values TR1, TR2 and the like of motor generators MG1, MG2 and the output voltage VB of power storage device 28, The target value calculation unit 330 calculates the command duty DUTY of the switching elements Q1 and Q2.

In S420, the ECU 30 sets the upper limit value UL and the lower limit value LL of the duty range that can be actually set in consideration of the dead time based on the carrier frequency FC and the set values of the dead times of the switching elements Q1 and Q2. The reference value calculation unit 340 performs calculation.

In S430, the ECU 30 determines whether the command duty DUTY is within the settable range, that is, whether LL <DUTY <UL.

If command duty DUTY is within the settable range (YES in S430), ECU 30 proceeds to S470 to generate carrier wave CAR as initial value (FC0) set to carrier frequency FC in S400. By comparing carrier wave CAR and command duty DUTY, control command PWC for switching elements Q 1 and Q 2 is generated and output to converter 12.

On the other hand, when command duty DUTY exceeds the settable range, that is, when DUTY ≦ LL or DUTY ≧ UL (NO in S430), the process proceeds to S440, and ECU 30 decreases carrier frequency FC. Change to

Then, the ECU 30 determines whether or not the carrier frequency lowered in S450 is greater than a preset reference value (lower limit value) of the carrier frequency. The reference value (lower limit value) of the carrier frequency is set in consideration of the control cycle of ECU 30 and the stability of control.

If the carrier frequency lowered in S450 is larger than a preset reference value (lower limit value) of the carrier frequency (YES in S450), the process proceeds to S470, and ECU 30 determines the changed carrier frequency. A carrier wave CAR according to FC * is generated, and a control command PWC for switching elements Q1 and Q2 is generated and output to converter 12.

On the other hand, when the carrier frequency lowered in S450 is equal to or lower than a preset reference value (lower limit value) of the carrier frequency (NO in S450), ECU 30 changes carrier frequency FC * after change in S460. Is set to the lower limit of the carrier frequency. ECU 30 then generates control command PWC and outputs it to converter 12 in S470.

By performing the control according to the processing as described above, the carrier frequency can be maintained at a high frequency within the settable voltage range of the target output voltage VHREF, so that noise generated by downsizing and switching of the converter 12 can be suppressed. You can enjoy the benefits of higher frequency. At the same time, when the output voltage is restricted at a low temperature or the like, the target output voltage can be obtained by suppressing the output voltage restriction by setting the carrier frequency low. Further, when the target output voltage VHREF exceeds the settable voltage range, a large current flows through the converter 12, so that the heat generation of the switching elements Q1, Q2 can be suppressed by reducing the carrier frequency. As a result, the heat resistance specifications of the switching elements Q1 and Q2 can be relaxed, and the specifications of the cooling facility (not shown) can be relaxed, so that the cost can be further reduced.

[Embodiment 2]
In the first embodiment, the configuration in which the settable voltage range is expanded by lowering the carrier frequency when the target output voltage VHREF exceeds the settable voltage range has been described.

In the second embodiment, when the target output voltage VHREF exceeds the settable voltage range, only one of the switching elements Q1 and Q2 is driven (hereinafter also referred to as “one-arm drive”). A configuration for expanding the settable voltage range by reducing the dead time period by performing switching control will be described.

FIG. 14 is a time chart for explaining the actual duty when the converter drive control according to the second embodiment is applied in the power running state of FIG.

When the reactor current IL is always positive, when the switching element Q2 is in an off state, a current flows through the diode D1 regardless of the operating state of the switching element Q1. Therefore, in such a state, even if the driving of the switching element Q1 is stopped, the current state is the same as in the case of driving both arms of the switching elements Q1 and Q2.

Here, since the driving of the switching element Q1 is stopped, the switching elements Q1 and Q2 are simultaneously turned on, and the power line PL2 and the ground line NL are not short-circuited. Therefore, basically, it is not necessary to consider the dead time. Further, it is not necessary to consider the minimum on-time of the switching element Q1.

As a result, the command duty can be set until the time T1 in FIG. 14 becomes equal to the minimum OFF time of the switching element Q2, so that the settable voltage range can be expanded. Depending on the state of the load, there may be a sudden change from power running to regeneration (or regeneration to power running), or a change from single-arm drive to double-arm drive. In that case, since the switching element to be driven is switched, even in the case of single arm driving, a dead time may be provided before the switching element to be driven is turned on as shown in FIG.

FIG. 15 is a functional block diagram for explaining converter drive control executed by the ECU 30 in the second embodiment. FIG. 15 is a block diagram in which the drive control unit 320 is replaced with the drive control unit 320A in the functional block diagram described in FIG. 12 of the first embodiment. In FIG. 15, the description of the functional blocks overlapping those in FIG. 12 will not be repeated.

Referring to FIG. 15, drive control unit 320A includes target value calculation unit 330, reference value calculation unit 340, selection unit 350A, oscillation unit 370, and drive command generation unit 380A.

The target value calculation unit 330 calculates a command duty DUTY based on these pieces of information. Then, target value calculation unit 330 outputs the calculation result to selection unit 350A and drive command generation unit 380A.

The reference value calculation unit 340 is based on the carrier frequency FC from the frequency setting unit 300 and the dead time and the minimum on-time of the switching elements Q1 and Q2. The value UL and the lower limit value LL are calculated. Then, the calculation result is output to the selection unit 350A.

The selection unit 350A receives the upper limit value UL and the lower limit value LL of the settable duty range from the reference value calculation unit 340 and the command duty DUTY from the target value calculation unit 330. Then, selection unit 350A selects either of the two-arm drive mode and the one-arm drive mode for driving only one of the switching elements Q1 and Q2 depending on whether or not the command duty DUTY is within the settable duty range. Select the mode. Specifically, selection unit 350A selects the both-arm drive mode when command duty DUTY is within the settable duty range. Further, when the command duty is equal to or greater than the upper limit value UL, the selection unit 350A selects the one-arm drive mode that drives only the lower arm (switching element Q2). Furthermore, when the command duty is equal to or lower than the lower limit value LL, the selection unit 350A selects the one-arm drive mode that drives only the upper arm (switching element Q1).

Then, the selection unit 350A outputs the selected drive mode selection signal SEL to the drive command generation unit 380A.

The oscillation unit 370 generates a carrier wave CAR according to the carrier frequency FC set by the frequency setting unit 300, and outputs the carrier wave CAR to the drive command generation unit 380A.

The drive command generation unit 380A receives the command duty DUTY from the target value calculation unit 330, the selection signal SEL from the selection unit 350A, and the carrier wave CAR from the oscillation unit 370.

Then, drive command generator 380A compares command duty DUTY with carrier wave CAR so as to drive the drive arm selected by selection signal SEL with command duty DUTY, and generates switching control command PWC to convert converter 12 Output to.

FIG. 16 is a flowchart for explaining details of converter drive control processing executed by ECU 30 in the second embodiment. FIG. 16 is obtained by adding S435, S436, S445, S446, S447, and S470A in place of the steps from S430 to S470 in the flowchart described in FIG. 13 of the first embodiment. In FIG. 16, the description of the same steps as those in FIG. 13 will not be repeated.

Referring to FIGS. 15 and 16, ECU 30 calculates the upper limit value UL and the lower limit value LL of the command duty DUTY based on the carrier frequency and the set values of the dead times of the switching elements Q1 and Q2 in S420. Then, the process proceeds to S435 to determine whether or not the command duty DUTY is equal to or less than the lower limit value LL.

When the command duty DUTY is equal to or lower than the lower limit value LL (YES in S435), the ECU 30 selects a one-arm drive mode for driving only the lower arm (switching element Q2) in S445.

On the other hand, if command duty DUTY is greater than lower limit value LL (NO in S435), the process proceeds to S436, and ECU 30 determines whether command duty DUTY is greater than or equal to upper limit value UL.

If command duty DUTY is equal to or greater than upper limit value UL (YES in S436), the process proceeds to S446, and ECU 30 selects a one-arm drive mode in which only the upper arm (switching element Q1) is driven in S446. .

On the other hand, when the command duty DUTY is smaller than the upper limit value UL, that is, when the command duty is within the settable range (NO in S436), the ECU 30 selects the both-arm drive mode in S447.

In S470A, the ECU 30 generates the carrier wave CAR as the initial value (FC0) set to the carrier frequency FC in S400, compares the carrier wave CAR with the command duty DUTY, and in S445, S446, or S447. A control command PWC is generated and output to converter 12 so as to control switching elements Q1 and Q2 in the selected drive mode.

By controlling according to such a process, it is possible to always drive at a high carrier frequency, and therefore, it is possible to enjoy the merit of high frequency, such as downsizing the converter 12 and suppressing noise generated by switching.

[Embodiment 3]
In the first and second embodiments, the settable range of the command duty DUTY is set based on the initial value (fixed value) of the carrier frequency FC set by the frequency setting unit 300 and the set time of the dead time, The configuration for changing the carrier frequency or selecting the drive arm when the command duty DUTY exceeds the settable range has been described.

In the third embodiment, a description will be given of a configuration in which the carrier frequency is set in advance when the carrier frequency FC is set and there is an influence of dead time.

By adopting such a configuration, the calculation function of the settable range of the command duty DUTY and the determination function based on the comparison between the settable range and the command duty are not required as in the first or second embodiment. The control process can be simplified.

FIG. 17 is a functional block diagram for explaining converter drive control executed by the ECU 30 in the third embodiment.

Referring to FIGS. 1 and 17, ECU 30 includes a frequency setting unit 300A, a voltage command setting unit 310, and a drive control unit 320B. The drive control unit 320B includes a target value calculation unit 330, an oscillation unit 370, and a drive command generation unit 380.

Frequency setting unit 300A includes output voltage VB of power storage device 28 detected by voltage sensor 10, output current IB of power storage device 28 detected by current sensor 11, current IL flowing through reactor L1 detected by current sensor 18, and The load power PR of the load device 45 is input. Then, the frequency setting unit 300A sets the carrier frequency FC by referring to a preset map based on these pieces of information.

18 to 20 are examples of maps for setting the carrier frequency FC. FIG. 18 is a first example of a map for setting the carrier frequency FC, and the carrier frequency FC is set based on the output power POUT (= VB × IB) of the power storage device 28. Note that carrier frequency FC may be set based on output voltage VB or output current IB of power storage device 28.

FIG. 19 is a second example of a map for setting the carrier frequency FC, and the carrier frequency FC is set based on the reactor current IL flowing through the reactor L1. FIG. 20 is a third example of a map for setting the carrier frequency FC, and the carrier frequency FC is set based on the load power PR of the load device 45.

Referring to FIGS. 1 and 17 again, voltage command setting unit 310 receives input of torque command values TR1, TR2 of motor generators MG1, MG2 and rotational speeds MRN1, MRN2 of motor generators MG1, MG2. Based on these pieces of information, voltage command setting unit 310 calculates voltage command value VHREF of input voltage (system voltage) VH of inverter 23, and outputs it to target value calculation unit 330.

The target value calculation unit 330 calculates a command duty DUTY based on these pieces of information. Then, the target value calculation unit 330 outputs the calculation result to the drive command generation unit 380.

The oscillation unit 370 generates a carrier wave CAR according to the carrier frequency FC received from the frequency setting unit 300A, and outputs the carrier wave CAR to the drive command generation unit 380.

FIG. 21 is a flowchart for explaining details of converter drive control processing executed by ECU 30 in the third embodiment.

Referring to FIGS. 17 and 21, ECU 30 shows carrier frequency FC in FIGS. 18 to 20 based on information such as output voltage VB, output current IB, reactor current IL of power storage device 28 in S405. Set by referring to such a map.

In S470, the ECU 30 generates a carrier wave CAR according to the carrier frequency FC set in S405, and compares the carrier wave CAR with the command duty DUTY to thereby control the switching elements Q1 and Q2. A PWC is generated and output to the converter 12.

By performing control according to the above processing, the carrier frequency in the range affected by the dead time can be set to be lowered in advance. As a result, since switching control can be performed at a high carrier frequency in a range where there is no influence of dead time, it is possible to enjoy the merit of high frequency, such as downsizing the converter 12 and suppressing noise generated by switching. At the same time, when the output voltage is limited at a low temperature or the like, the target output voltage can be obtained by suppressing the output voltage limitation by setting the carrier frequency low.

[Modification of Embodiment 3]
In the third embodiment described above, the carrier frequency FC is set in advance in consideration of the effect of dead time. However, depending on the actually calculated command duty DUTY, it may exceed the settable range of the command duty. There is sex.

Therefore, in the modification, a configuration in which the third embodiment is combined with the first embodiment or the second embodiment will be described.

FIG. 22 is a functional block diagram for explaining converter drive control executed by the ECU 30 when the first embodiment and the third embodiment are combined. In FIG. 22, the frequency setting unit 300 in the functional block diagram described in FIG. 12 in the first embodiment is replaced with the frequency setting unit 300A in the third embodiment. Since each functional block is the same as that described with reference to FIGS. 12 and 17, detailed description thereof will not be repeated.

FIG. 23 is a flowchart for explaining details of converter drive control processing executed by ECU 30 when the first embodiment and the third embodiment are combined. In FIG. 23, step S400 in the flowchart in FIG. 18 described in the first embodiment is replaced with step 405 in FIG. 21 described in the third embodiment. Therefore, detailed description of each step will not be repeated.

Although not shown, a configuration in which the second embodiment and the third embodiment are combined may be possible. In this case, the frequency setting unit 300 in the functional block diagram of FIG. 15 is replaced with the frequency setting unit 300A of the functional block diagram of FIG. 17, and step S400 in the flowchart of FIG. 16 is replaced with step S405 of the flowchart of FIG. This can be realized by replacing it with. The description of each functional block and each step will not be repeated.

Thus, by further applying the third embodiment to the first or second embodiment, the output voltage limitation caused by the dead time can be suppressed in the converter 12.

The converter 12 in the present embodiment is an example of the “voltage conversion device” in the present invention.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

10, 13 voltage sensor, 11, 18, 24, 25 current sensor, 12 converter, 14, 22, 23 inverter, 15 U phase upper and lower arm, 16 V phase upper and lower arm, 17 W phase upper and lower arm, 20 DC voltage generator, 26, 27 rotation angle sensor, 28 power storage device, 30 ECU, 40 engine, 41 power split mechanism, 42 drive wheels, 45 load device, 100 hybrid vehicle, 300, 300A frequency setting unit, 310 voltage command setting unit, 320, 320A , 320B drive control unit, 330 target value calculation unit, 340 reference value calculation unit, 350, 350A selection unit, 360 frequency change unit, 370 oscillation unit, 380, 380A drive command generation unit, C1, C2 smoothing capacitors, D1 to D8 Diode, L1 reactor, MG1, MG Motor generator, NL ground line, PL1, PL2 power lines, Q1 ~ Q8 switching element, SR1, SR2 system relay, V0 connection node.

Claims

A control device (30) of the voltage conversion device (12) capable of voltage conversion between the power storage device (28) and the load device (45),
The voltage converter (12)
A first switching element (Q1) and a second switching element (Q2) connected in series between a power line (PL2) and a ground line (NL) of the load device (45) and performing the voltage conversion by a switching operation. )
The switching operation is
A dead time which is a period in which both the first switching element (Q1) and the second switching element (Q2) are in an off state;
The control device (30)
A frequency setting unit (300, 300A) for setting a carrier frequency of the switching operation;
A drive control unit (320, 320A) configured to control the switching of the first switching element (Q1) and the second switching element (Q2) based on the voltage command value of the voltage conversion and the carrier frequency. 320B),
The drive control unit (320, 320A, 320B) outputs the voltage converter (12) limited by the dead time based on information related to power input / output to / from the voltage converter (12). A control device for a voltage converter that performs switching control of the first switching element (Q1) and the second switching element (Q2) so as to expand a possible voltage range.
The information related to the power input / output to / from the voltage converter (12) is the target duty of the first switching element (Q1) and the second switching element (Q2),
The drive control unit (320, 320A)
A target value calculation unit (330) configured to calculate the target duty based on the voltage command value;
A reference value calculation unit (340) configured to calculate a duty range that determines the output possible voltage range based on the carrier frequency and the dead time;
2. The voltage conversion according to claim 1, wherein, when the target duty exceeds the duty range, the drive control unit (320, 320 A) performs the switching control so as to expand the output possible voltage range. Control device for the device.
The drive control unit (320)
The control device for a voltage converter according to claim 2, further comprising a frequency changing unit (360) configured to decrease the carrier frequency when the target duty exceeds the duty range.
The drive control unit (320A)
When the target duty exceeds the duty range, one of the first switching element (Q1) and the second switching element (Q2) is selected while the target duty is within the duty range. A selector (350A) configured to select both the first switching element (Q1) and the second switching element (Q2),
The control device for a voltage converter according to claim 2, further comprising a drive command generation unit (380A) that generates a drive command for the switching element selected by the selection unit (350A).
The control device for a voltage converter according to claim 4, wherein the selection unit (350A) selects the second switching element (Q2) when the target duty is larger than an upper limit value of the duty range. .
The control device for a voltage conversion device according to claim 4, wherein the selection unit (350A) selects the first switching element (Q1) when the target duty is smaller than a lower limit value of the duty range. .
2. The voltage conversion according to claim 1, wherein the frequency setting unit (300 A) variably sets the carrier frequency based on information related to power input / output to / from the voltage conversion device (12). Control device for the device.
8. The information according to claim 7, wherein the information related to the power input / output to / from the voltage conversion device (12) includes at least one of output power, output voltage, and output current of the power storage device (28). Control device for voltage converter.
The voltage converter (12)
A reactor (L1) provided in a path connecting a connection node between the first switching element (Q1) and the second switching element (Q2) and a positive electrode terminal of the power storage device (28);
The control device for a voltage conversion device according to claim 7, wherein the information related to the electric power input / output to / from the voltage conversion device (12) includes a reactor current flowing through the reactor (L1).
The control device for a voltage converter according to claim 7, wherein the information related to the power input / output to / from the voltage converter (12) includes power supplied to the load device (45).
[Correction based on Rule 91 17.06.2010]
A vehicle (100),
A power storage device (28);
Rotating electric machines (MG1, MG2) for generating a driving force for propulsion of the vehicle (100);
An inverter (23) for driving the rotating electrical machine (MG1, MG2);
A voltage conversion device (12) configured to be capable of voltage conversion between the power storage device (28) and the inverter (23);
A control device (30) for controlling the voltage converter (12),
The voltage converter (12)
A first switching element (Q1) and a second switching element (Q2) connected in series between a power line (PL2) and a ground line (NL) of the inverter (23) and performing the voltage conversion by a switching operation. Including
The switching operation is
A dead time which is a period in which both the first switching element (Q1) and the second switching element (Q2) are in an off state;
The control device (30)
A frequency setting unit (300, 300A) for setting a carrier frequency of the switching operation;
A drive control unit (320, 320A) configured to control the switching of the first switching element (Q1) and the second switching element (Q2) based on the voltage command value of the voltage conversion and the carrier frequency. 320B),
The drive control unit (320, 320A, 320B) outputs the voltage converter (12) limited by the dead time based on information related to power input / output to / from the voltage converter (12). A vehicle that performs switching control of the first switching element (Q1) and the second switching element (Q2) so as to expand a possible voltage range.
The information related to the power input / output to / from the voltage converter (12) is the target duty of the first switching element (Q1) and the second switching element (Q2),
The drive control unit (320, 320A)
A target value calculation unit (330) configured to calculate the target duty based on the voltage command value;
A reference value calculation unit (340) configured to calculate a duty range that determines the output possible voltage range based on the carrier frequency and the dead time;
The vehicle according to claim 11, wherein the drive control unit (320, 320A) performs the switching control so as to expand the output possible voltage range when the target duty exceeds the duty range.
The drive control unit (320)
The vehicle according to claim 12, further comprising a frequency changing unit (360) configured to decrease the carrier frequency when the target duty exceeds the duty range.
The drive control unit (320A)
When the target duty exceeds the duty range, one of the first switching element (Q1) and the second switching element (Q2) is selected while the target duty is within the duty range. In the case of the selection unit (350A) configured to select both the first switching element (Q1) and the second switching element (Q2),
The vehicle according to claim 12, further comprising: a drive command generation unit (380A) that generates a drive command for the switching element selected by the selection unit (350A).
A method for controlling a voltage converter (12) capable of voltage conversion between a power storage device (28) and a load device (45),
The voltage converter (12)
A first switching element (Q1) and a second switching element (Q2) connected in series between a power line (PL2) and a ground line (NL) of the load device (45) and performing the voltage conversion by a switching operation. )
The switching operation is
A dead time which is a period in which both the first switching element (Q1) and the second switching element (Q2) are in an off state;
The control method is:
Setting a carrier frequency of the switching operation;
Switching control of the first switching element (Q1) and the second switching element (Q2) based on the voltage command value of the voltage conversion and the carrier frequency;
Based on the information related to the electric power input / output to / from the voltage converter (12), the first switching is performed so as to expand the output possible voltage range of the voltage converter (12) limited by the dead time. And a step of controlling switching of the element (Q1) and the second switching element (Q2).